Of all the "Uber for __" propositions, the splashiest by far was Blackjet, the app that purports to help wealthy users book seats on private jets (for a $2,500 annual membership fee). When it launched last October, the company touted A-list Hollywood investors like Ashton Kutcher, Jay Z, and Will Smith, not to mention connections to successful—or successful-seeming—companies like Uber. But sources tell Valleywag that Blackjet is in a tailspin—out of cash, unable to raise funds, and "basically over." Another source said: "They are fucked."

The idea behind Blackjet was that, after ponying up that hefty membership fee, users would be able to seamlessly book seats on a private jet wherever they needed to go "in 10 seconds, with guaranteed availability," as the web site puts it. Like Uber, the company operates as a middleman, taking a cut of the proceeds for building an automated interface to fill empty seats. It doesn't own any jets or employ any pilots, but rather establishes relationships with private carriers.

Just over a year after launching, though, the only customer review on Blackjet's iPhone app called the service "horrible," complaining about the one month approval process after paying the $2,500 fee: "I've had less hassle getting into the White House (and I'm not kidding about that)." A source told Valleywag that Blackjet members haven't been able to book seats for the past two months.

But when investments go south, people look for someone to blame. In Blackjet's case, part of that has fallen on the company's flamboyant former chairman Shervin Pishevar, who also invested in the Blackjet and was instrumental in securing funding for Uber. According to one source, Pishevar promised the Hollywood crowd and Silicon Valley insiders who invested $2.4 million in Blackjet that he would be able to raise $15 to $20 million, including money from his new fund Sherpa Ventures. But that financing didn't come through.

Part of the difficulty in raising funds, one source told Valleywag, stems from the fact that the established venture capital firms that line Menlo Park's Sand Hill Road refused to join Pishevar on a deal because of the noise he generates. "He is obsessed with being liked and famous," a source said. "It's not gonna end well."

In February, Pishevar left a plum role as managing partner of Menlo Ventures to start Sherpa with Goldman Sachs banker Scott Stanford—riding the wave of investments he worked on at Menlo, like financing for Uber, Fab.com, TaskRabbit, and Tumblr.

Investors are a cliquey bunch, but it's hard to picture venture capitalists abstaining from a hot company, no matter how loud it gets. His over-sharing didn't hurt Pishevar's ability to lock down $15 million of the $150 million he is hoping to raise for Sherpa from TPG Capital, the private equity firm that recently joined a $258 million investment round in Uber.

Pishevar declined to comment. But one glance at his public Instagram and Twitter accounts shows he's rarely met a bold-faced name he didn't @. He posted photos of Miley Cyrus backstage at the VMAs on the night of the tongue wag heard 'round the world. And that's him hanging with Kanye West after dinner with Elon Musk.

One reason Pishevar, who became Blackjet's chairman in 2012 and stepped down a few months ago, is being singled out is because he was positioned in the tech press as playing a pivotal role in the formation of the company. During an eye-catching Blackjet event in San Francisco in February, which featured the Blackjet SkyAngels (booth babes for the private jet set), Pishevar said he was responsible for bringing in Uber cofounder Garrett Camp on as a Blackjet "cofounder." After all, it's much easier to sell Silicon Valley on "Uber for private jets" when you have Uber DNA, no?

"With the new app, you push a button, then you're booked. Then you take your Uber to your Blackjet, and take off. So it's pretty exciting. I think that's the way the world is going to work. It's a lot more efficient, no more waste."

Not everyone puts the blame on Pishevar. One source attributed Blackjet's failure to raise funds to the company's decision to try to secure a higher valuation, noting that fundraising obligations fall on the CEO, not the chairman. The market is still early and different models are being experimented with, said the source. Companies like Surfair, which is using a Netflix "all you can fly" model," are supposedly raising a big round of capital to expand, whereas the Blackjet model hasn't been working as well.

"I think the airlines, they may not embrace it but they can understand that this whole different system is probably going to be something they can leverage," suggests Rocthin. "So we think that we would be acquired by them. We've already been in contact with a couple of airlines."

A source cautioned: "Acquired in this sense may mean some assets are sold for $1 million."

In response to questions from Valleywag, Rotchin sent the following statement:

BlackJet members are truly early adopters of a new technology and model that is disruptive to air travel by reducing the cost to fly private by 80%. We have had tremendous support since our launch. We are focusing on providing charter flights now, while evaluating long term financing alternatives. We remain dedicated to our mission to provide the ultimate affordable private jet travel experience to our members.

Regardless of where the company lands, Blackjet's problems also shine a spotlight on the unpredictable impact of celebrity investors and their social media sway. (Will Smith invested through Overbrook Entertainment, Jay Z through Roc Nation, whereas Ashton Kutcher and Guy Oseary invested personally, according to Crunchbase.) Blackjet gave Miley Cyrus a ride to Silicon Valley and the pop star was "given some consideration for her tweet," Rotchin told the New York Times.